Metal tubing bending machine



F. L. DUER METAL TUBING BENDING MACHINE Feb. 8, 1944.

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Feb. 8, 1944. F. L. DUER 2,341,178

METAL TUBING BENDING MACHINE Filed Dec. 6, 1941 :s'sheets-sheet 2 INVENT OR.

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F. L. DUER 2,341,178

METAL TUBING BENDING MACHINE Filed Dec. 6, 1941 3 Sheets-Sheet 3 INVENTOR.

Patented Feb. 8, 1944 UNITED STATES PATENT OFFICE 2,341,178 METAL TUBINGBENmNG MACHINE Frederick L. Duer, Chicago, 111. Application December 6,1941, Serial 1V0. 421,924

2 Claims. (01. 153-40) L This invention relates to improvements in metaltubing bending machines, such as described and claimed in my co-pendingapplication for Letters Patent, Serial No. 399,301, filed June 23, 1941,and more particularly, the invention has reference to an improved jigfor machines of such character, having for an object to provide a jigespecially advantageous for use in connection with those types ofbending machines wherein a succession of annular bends of pre-determineddegrees are required to be made in tubular, strip or similar stockduring the formation of products, such for example, as chair frames,table frames, legs, supporting stands, etc.

It is also an object of the invention to provide a jig for metal bendingmachines having stock guide means thereon so positioned that when thesame are individually employed in' association with that stock to bebent by the machine, the stock will be arranged in relation to the metalbending form of the machine so as to be bent at a pre-determined point,hence, insuring accurate and proper formation of an ultimately finishedproduct and moreover, accurate reproduction of similar products.

Yet another object of the invention is to provide a jig of the statedcharacter which is so constructed that by its use in connection with a.metal bending machine, the operating .time normally required for themaking of a multiplicity of accurate bends in material or stock will begreatly reduced, hence, afiording increased production tubing inposition with respect to a portion of the skilled in the art to which itappertains, I have in the accompanying drawings and the detaileddescription based thereupon, set out one embodiment of my invention. I

In the drawings: Figure 1 isa top plan view of a metal tubing bendingmachine equipped with my improved jig.

Figure 2 is a side elevation of the same,

Figure 3 is a combined schematic and perspecjig for making a fifth bendtherein.

Figure 'l is a similar view illustrating the thus far bent metal tubingin position, with respect to a portion of the jig, for the making of asixth bend therein.

Figure 8 is a like view showing the metal tubing in position withrespect to the machine bending form and a portion of the improved jig,for the making of a seventh bend therein.

Figure 9 is a corresponding view wherein the metal tubing stock is inposition with respect to the machine bending form and a portion of thejig, for the making of the 8th bending therein, and

Figure 10 is'a perspective view of a completed chair form produced orbent upon the improved jig equipped machine in accordance with thesuccessive steps of bending illustrated by the Figures 3 to 9,inclusive.

Having more particular reference to the drawings, in connection withwhich like characters of reference will designate corresponding partsthroughout, the improved jig is particularly advantageous for use inconnection with that type of metal bending machine described and claimedin my co-pending application for patent, aforesaid, which machineincludes a horizontal bed I mounted on a suitable support (not shown)having a secondary bed 2 fixed to its normally forward end shown inFigures 1 and 2 of the accompanying drawings. A rotatable bending form 3is positioned on the upper side of the secondary bed 2, in which avertical shaft 4 is journaled and has a gear 5 on its lower end. Rotarymotion is selectively transmittable to the gear 5 through a horizontalrack bar 6 supported by the beds 1 and 2, thesteeth of said barmeshingwith those of the gear To secure tubing or other stock to be bent by themachine, a work clamp l is mounted on the upper side of the secondarybed 2 in suitable relation to the bending form 3. By engaging a lengthof tubing in the clamp at an appropriate point and adjacent the bendingform, it will be seen that with rotation of said form, said tubing willbe bent thereby to the desired angular degree.

In order that the tubing or other stock to be bent upon the machinemaybe caused to be bent or successively bent at pre-deterznined pointsthroughout its length, whereby to effect an accurate and satisfactoryproduct, I provide my 1 proved jig. Prefatorially, it may be stated thatthis improved jig may be adjusted or set to facilitate making of amultiplicity of predetermined bends in stock at various pointsthroughout its length, and when correctly employed, will insure faithfulreproduction or replica production of products by the equipped machine.

The jig, in general, comprises a plurality of guides and stops or restswith which the stock to be bent during a particular production job is engaged at certain predetermined points thereon, whereupon the bendingoperations of an equipped machine are efiected, resulting in a productwhich is capable of detailed accurate reproduction in all othersubsequently produced pieces. The relative arrangement of the guides andstops is such that angular bends of desired degrees will be made in thestock material at predetermined points throughout its length and also,that such bends may be effected in relatively different planes so thatcomplete formation of a product may be accomplished by a single machinethrough a continuous succession of predetermined machine bendingoperations.

Fixedly connected at one end to an appropriate upper portion of thesecondary bed 2 through the medium of screws or other suitable fasteningmeans 8 is a supporting arm 9. Slidably received upon and disposedlongitudinally of the arm 9 in juxtaposed relation are a pair of bars inand H having relatively upstanding and right angularly disposed fingersill and ii fixed on their normally inner end portions. Each of the barsis longitudinally slotted, as at I2 and [3 whereby to receive lockingscrews i4 and I5 therethrough. The locking screws are turned intoengagement with appropriate portions of the arm 9 and in consequence,serve to confine the paths of longitudinal sliding movement of theirrespective bars I and II. Adjusting screws it are engaged through screwthreaded openings formed in the fingers ill and II and have their headsin bearing arrangement upon adjacent portions of the secondary bed 2.Thus, by turning the adjusting screws l6,suitable longitudinal slidingadjustment of their respective bars l0 and II upon the arm '9 will beeffected, whereupon said bars may be'locked in their respectivelyadjusted positions by tightening of the screws l4 and I5. An upstandingguide pin I1 is fixedly carried upon the normally outer end of the bar1- and the corresponding end of the bar II is formed longitudinal orhorizontal adjustability with respect thereto. An angle arm 26 issecured to the upper end of the rest 24 inwardly of its outer end and atsubstantially right angles thereto, while an adjustable stop bolt 21 isengaged through the upper part of said rest 24 and the adjacent portionof the angle arm 26. In this connection, it will be noted that theadjustable stop bolt 21 is arranged in substantially parallelism to theright angularly disposed portion of the arm 26 and that its free end isinwardly placed with relation to the outer end of said arm.

A second horizontally arranged supporting arm 28 is rigidly connected toan appropriate portion .of that side of the secondary bed 2 in proximityto the point of connection of the arm 20 therewith. Said arm 28,however, is disposed at substantially right angles to the arm 20 andcarries a standard 28' on its outer end, which, in turn, carries a rigidhorizontally arranged and longitudinally disposed arm 28, the forwardend of which is provided with a rigid standard 28 carwith a transverselydisposed extension I8 on outwardly beyond the forward end of the bed Ito a point beyond the arm 9 and, as will be noted upon reference-toFigureZ of the accompanying drawings, is arrang'edin a plane below'thatin which said arm} s a'rranged. A facing plate 22 ispositionedlononeiside of the. outer portion ofthe arm' 20 provides aslidable bearing for rying an oblique and forwardly disposed supportingarm 28 upon its outer end. A facing plate 29, corresponding to thefacing plate 22, is fixed to one side of the free end of the supportingarm 28 and has a horizontal longitudinally slotted finger 30 slidablyconnected thereto through the medium of locking screws 3| passed throughthe slot of said finger into engagement with appropriate screw threadedopenings in the facing plate 29. Secured to the outer side and forwardend of the longitudinally slotted finger is a horizontally arrangedangle arm 32, corresponding to the angle arm 26, while an adjustablestop bolt 33, arranged in parallelism to the arm 32, and

corresponding to the bolt 21, is also engaged with said finger 30; theouter end of such stop bolt being spaced inwardly with relation to itsadjacent angle arm 32, as clearly shown in Figure 1 of the accompanyingdrawings.

It is to be noted that the relative arrangement of the angle arms 25 and32 and their respective adjacent adjustable stop bolts 21 and 33 is suchthat they are disposed in substantially vertical or perpendicularalignment, the latter above the former, hence, that but one (the arm 32,the stop bolt 33 and its finger 30) is shown in Figure 1 of thedrawings;

The horizontal arm 28 is provided upon its normally inner side with afixedly arranged facing plate 34 adjacent which a slotted finger 35 ispositioned and is adapted to have adjustable sliding movement withrespect thereto through the medium of adjusting or looking screws 36engaged through the slot of said finger 35 and in appropriate screwthreaded openings formed in the facing plate 34. The outer or normallyforward end of the finger 35 is shouldered as at 31 and carries a rightangularly disposed vertical portion 38 to which a longitudinally slottedarm 39 is slidably connected by passing looking or adupon referencetoFigures 1 and 2 of the accome the longitudinallyslotted finger 23carrying an upright-rest uponits outer end. Connecting or lookingscrews. 2 5 are engaged through the ioni u inal ot-oi he' a r H d inappropria screw threaded 1 openings formed in the facing pla 22;; huarvi n's for s p rti co panying drawings, extends for a distance outwardlybeyond the shouldered portionl'l' of the finger 35. The arrangementofthe finger 35 on the horizontal arm 28 is such that the'upperex-'tremity of the arm as and its laterally extending lip or rest 41 arearranged ins-horizontal plane v tionrofv tattleplate and also, for 7'5corresponding to; that mwhich .the rotatable bending form 3 is arranged.as will be observed upon reference to Figure 2 of the drawings.

In order that tubing T engaged with the supporting arm 3, in the mannershown in dotted lines in Figure 1 of the drawings, will be efl'ectuallyretained in the Proper horizontal plane,

The bearing plate 43, in turn, receives a vertically adjustable rest 44adjacent its outer side, said rest being in form of a sheet-like metalplate having a horizontally and rearwardly extendedsupporting finger 45formed thereon. Vertical adjustment of the plate 44 is effected byengaging screws 46 through vertical slots 41 formed in said plate andinto engagement with appropriately formed screw threaded openings in theplate 43. Thus, it will be understood that the rest 44 may be verticallyadjusted to support the outer end of tubing engaging the same in thedesired position or horizontal plane.

In operation of my improved jig, and assuming the same to be installedupon that type, of bending machine partially shown in the accompanyingdrawings and heretofore generally described, the component parts of thejig are preadjusted to proper positions for the particular bending jobto be performed. In the instant embodiment of the invention, the jig hasbeen set for usage in the production of a type of tubular metal chairframe such as shown inFigure 10 and identified in its entirety by thereference character 0. Metal tubing of the required diameter or size andof the proper length, is engaged, at a predetermined point throughoutits length, with the metal bending form 3. The'reupon, it is secured bythe work clamp l and the bending form 3 is rotated through the gearingconnected thereto so as to form the first bend-a right angular bend48-in the tubing. With the first bend thus made, the tubing isdisengaged from the work clamp 1 and from the bending form 3. It ismoved outwardly with respect to the machine until the right angular bend48 is engaged aboutv and adjacent the guide finger [1. When so engaged,it will be seen that the right angular outer leg portion of the tubing Tis supported in the proper horizontal plane by the adjacent portion ofthe arm 9 and by the normally innerportion of the upper edge or marginof the adj d r t M, in the manner shown in Figure 3. At such time, theinner leg of the metal tubing T will be properly arranged adjacent thenear side of the bending form. 3 and will be secured through the workclamp l. The bending form 3 is now r0- tated to the proper degree, thusforming a second right angular bend in the tubing, indicated by thenumeral 49, in the Figure 4, The bent tubing T is now disengaged fromthe work clamp I and the bending form 3 and readjusted with respectthereto, whereupon it is reclamped by the work clamp I in that positionillustrated by Figure 4, which constitutes the position of the tubingfor making the third bend therein. In order that such third bend may beaccurately effected in the tubing and in that side or leg of the sameengaged adjacent the bending form,3, the looped or right angularlyformed end portion constituted by the bends 48 and 43, is moved untilthe outer portion, i. e., the bend 43, is engaged over the angle arm 32carried by the slottedfinger 33. The adjacent portion of the tubing isbrought into firm contact with the adjacent end of the previouslyadjusted stop bolt 33 so as to assure the making of such third bend inthe proper plane, which, as will be noted upon reference to the Figure3, is to be effected 111 8 plane at right Y angles to that at which thebends 43 and 43 were made. At this time, the bending form 3 is 1'0-tated so as to eflect a degree or right angular bend it in the adjacentportion of the metal tubing T. Following the making of the third bend inthe tubing, the thus far formed product is again disengaged from thework clamp 1 and rearranged with respect to the metal bending form 3.The portion provided with the bends 43, f

43 and I3 is arranged in a substantially vertical plane, as shown inFigure 5, with the outer end of the same supported upon an appropriateportion of the upper edge of the vertically adjusted rest 44 and thebend 50 engaged about the adjacent and previously adjusted guide fingerl3. Thereupon, the metal bending form is rotated to form a fourth and 90degree or right angular bend il in the adjacent portion or the tubing,

by reason of positioning of the work piece in course of production uponthe jig, that the free portion of the tubing T beyond the bend will bein absolute parallelism to the corresponding side of the previously benttubing, to constitute one side of the seat supporting portion of thechair frame being made. To constitute one side of the back of thetubular metal chairframe, it now becomes necessary to effect a fifthbend in that side of the tubing formed with the bends 50 and 5|.Accordingly, said side of the tubing is readjusted with respect to thework clamp l and the metal bending form 3 to that position shown inFigure 6. a That portion of the tubing adjacent the bend to is engagedwith and supported upon the previously adjusted rest 4|, andparticularly, the lip portion of the same in contact with the shoulderedportion 31 on the outer or normally forward end of the finger 35. Whenthus arranged, the piece being produced will be so positioned that asthe metal bending form 3 is again rotated to the desired degree, a lessthan right angular bend 52 will be eifected in the adjacent portion ofthe tubing so that the now free or outer end of the tubing constitutesone side of a slightly inclined back for the chair frame.

At this point, it should be explained that one complete side of thechair frame has now been produced and the following operation or bendingof the tubing T is effected to produce the opposite side of the chairframe. The piece is reversed in position and the remainingor unbent sideof the length of tubing is engaged with the work clamp I and the metalbending form 3 in the manner shown in Figure 7 of the accompanyingdrawings. In such position, it will be observed that the basal portionof the chair frame, 1. e., that portion having the bends 43, 43 and 50formed therein, is arranged in a vertical plane, its outer end beingengaged over and about the angle arm 26 of the upright rest 24 and inabutting engagement with the adjacent or free end of the previouslyadjusted stop bolt 21. With securing of the tubing adjacent the bendingform 3 by the work clamp 1, said bending form is now rotated to form a90 degree or right angular bend 53 therein. With forming of the rightangular bend 53, the work piece is vertically adjustable .rest '44 inthe manner shown in Figure 8; also, that portion of the tubing havingthe bend 53' formed therein is engaged about and'adja'cent the guidefinger I! of the bar II. The work clamp is engaged with the adjacentportion or side of the work piece and the bending form is rotatedwhereby to effect a right angular bend' 54 therein. At this point, itwill be noted that that portion of the tubing outwardly of the bend 54will be arranged in parallelism to the corresponding side of the basalportion of the chair frame, and thus, will constitute the opposite sideof the chair frame seat receiving portion. Following its release fromthe work clamp i, the work piece is readjusted with respect to the jigso that the bend 58 is received upon the rest 4! of the arm 89 adjacentthe shouldered portion 31 of the finger 35 in the manner illustrated inFigure 9 of the accompanying drawings. The work clamp i is nowre-engaged with the adjacent portion of the tubing T of the work piecand the metal bending form 3 is rotated to effect a slightly less thenright angular bend 55 in the tubing, thereby constituting the inclinedopposite side of the chair frame back.

A chair frame made according to the above described operation,heretofore characterized by the reference character C (Figure 10) maynow be provided with a suitable type of seat S and back B.

The construction and operation of my improved jig is such that thevarious bends and duplicating bends in the opposite or opposed portionsof the chair and tubing stock will absolutely cor-,- respond and inconsequence, will insure the production of a metal tubing chair framewhose opposite sides are replicas one of the other. Moreover, theconstruction of the improved jig and its operation is such that rapidreproduction of tubular metal chair frames may be effected by its usagewith a resultant material lowering of production costs, including time,labor, etc.

Whereas I have herein illustrated and described my improved jig asadapted for usage in the forming or production of tubular metal chairframes, it is, of course, to be fully understood that such Jig may be asadvantageously employed in guiding the formation of variousconstructions or products, such for example, as bed frames, benchframes, table frames, etc. When such adaptations of the jig areeflected, the various guide fingers, rests, and like elements ofconstruction are, as will be understood, so relatively adjusted topre-determined positions as to insure accurate and proper placement ofbend formations.

I claim:

1. A jig for bending machines, comprising an arm secured to andextending forwardly of the machine, longitudinally adjustable bars onsaid arm, guide means carried by each of said bars, an adjustable restsupported from and laterally of said arm, substantially opposedsupporting arms secured to and extending forwardly of the machinearranged in planes different from that of the first arm, adjustableguide means on each of said supporting arms, adjustable stop means onthe supporting arms cooperatively associated with said last mentionedguide means, and a 7 second adjustable rest supported on a portion ofone of said supporting arms in substantially laterally opposed relationto said first rest.

2. A jig for bending machines, comprising an arm secured to andextending beyond the work receiving end of the machine, adjustablebodies on said arm, guide means on said adjustable bodies, adjustablesupporting means carried by said arm and disposed laterally thereof,supporting arm respectively secured to and extending forwardly of themachine work receiving end above and below the first mentioned arm,guide ineanson each said supporting arm, stop means on the supportingarms co-Operatively associated with the last mentioned guide means, anda second adjustable means supported on a portion of one of saidsupporting arms and arranged in substantially-laterally opposed relationto said first adjustable means.

FREDERICK L. DUER.

